[antlr-interest] Proglem about the root of ASTree

Bryan Ewbank ewbank at gmail.com
Thu Sep 21 05:40:31 PDT 2006


Yes, this is a restriction - the '^' has to be at a token, because
that way it's guaranteed to be a single tree node. Rewrite it this
way:

        test : ID ( ">"^ | "<"^ ) expr ;

Hope this helps,
- Bryan Ewbank

On 9/21/06, sishen <sishen_freecity at 126.com> wrote:
> I set buildAST = true;
>
> I found something doesn't work when i defined a root.
>
>
> for example:
>
> test :  ID  op expr
>
> op:
>          ">"
>     |   "<"
>     ;
>
>
> i want "op"  to be the root of  expression.
> but i can't just write  "op^".  it's a  fault.
>
> However, when i write op  suffix  the operator ">"/"<".  it's also unuseful.
>
> What should i do?   thx all~
>
>


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